The present invention relates to a safety device, in particular for an overhead door, comprising fastening means for blocking the door, which means are operated by an auxiliary cable under tension, which is connected on the one hand to the door and on the other hand to a reel provided with a speed-limiting means, the latter blocking the reel and hence the auxiliary cable when the door exceeds a predetermined rate of descent and the fastening means becomes operative.
A safety device of this kind is known for a lift from French Pat. No. 384,422. In this patent, the auxiliary cable is directly connected to the fastening means, which in this case consists of a wedge-shaped element. If the lift becomes too fast the auxiliary cable blocks and the wedge-shaped element is displaced relative to the lift and consequently in turn blocks the lift.
This construction has the disadvantage that the safety device does not work if the auxiliary cable breaks or when the latter is not tensioned for other reasons.